diff options
Diffstat (limited to 'src/ivysocket.c')
| -rw-r--r-- | src/ivysocket.c | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/src/ivysocket.c b/src/ivysocket.c index 9d40f3d..582d227 100644 --- a/src/ivysocket.c +++ b/src/ivysocket.c @@ -579,3 +579,39 @@ void SocketSendBroadcast (Client client, unsigned long host, unsigned short port perror ("*** send ***"); } va_end (ap ); } + +/* Socket Multicast */ + +int SocketAddMember(Client client, unsigned long host ) +{ + struct ip_mreq imr; +/* +Multicast datagrams with initial TTL 0 are restricted to the same host. +Multicast datagrams with initial TTL 1 are restricted to the same subnet. +Multicast datagrams with initial TTL 32 are restricted to the same site. +Multicast datagrams with initial TTL 64 are restricted to the same region. +Multicast datagrams with initial TTL 128 are restricted to the same continent. +Multicast datagrams with initial TTL 255 are unrestricted in scope. +*/ + unsigned char ttl = 64 ; // Arbitrary TTL value. + /* wee need to broadcast */ + + imr.imr_multiaddr.s_addr = htonl( host ); + imr.imr_interface.s_addr = INADDR_ANY; + if(setsockopt(client->fd, IPPROTO_IP, IP_ADD_MEMBERSHIP, (char *)&imr,sizeof(struct ip_mreq)) == -1 ) + { + perror("setsockopt() Cannot join group"); + fprintf(stderr, "Does your kernel support IP multicast extensions ?\n"); + return 0; + } + + if(setsockopt(client->fd, IPPROTO_IP, IP_MULTICAST_TTL, (char *)&ttl, sizeof(ttl)) < 0 ) + { + perror("setsockopt() Cannot set TTL"); + fprintf(stderr, "Does your kernel support IP multicast extensions ?\n"); + return 0; + } + + return 1; +} + |